[EnergyPlus_Support] Re: Zone Equipment List problems

["eduardcubi" <eduardcubi@xxxxxxxx>]

Thank you so much for your clear explanation!

Eduard

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
<mjwitte@...> wrote:
>
> This model has an air loop VAV with reheat and radiant hydronic
cooling serving 
> the same zones, and both system are autosized.
> 
> 1.  EnergyPlus autosizing does not understand if there is more than
one system 
> serving the same zone.  It will size both system to meet the full
cooling load.
> 
> 2.  In the input file, the VAV terminal unit is priority 1 for
cooling, and the 
> radiant hydronic is priority 2.  So, if the VAV unit can meet the
thermostat 
> setpoint (which it will since it has been autosized), then there is
no load 
> remaining for the radiant cooling to serve.
> 
> 3.  So, revsersing the cooling priorities in zone 1N results in the
radiant 
> hydronic system showing flow, and the VAV box sitting a min flow.
> 
> 4.  However, in milder weather, the zone will probably overcool due
to the min 
> flow from the VAV box and the reheat will come on, which is not what
you want.  
> So, you will probably need to hand size one of both systems in order
to share 
> the load.  And you need to decide which system should be priority 1
and 2.
> 
> Mike
> 
> 
> On 6 Sep 2007 at 21:48, eduardcubi wrote:
> 
> > Hi all,
> > 
> > I have some problems when including radiant cooling systems in the
> > zone equipment list. 
> > It seems that when I assign the systems to their respective zones
> > (e.g. "z1N Radiant Ceiling" under "z1N Equipment") these don't work
> > (i.e. there is no temperature gain from the inlet to the outlet, and
> > the flow rate is 0). However, if I "do a mess" with the assignations,
> > it "works" (e.g.  "z1E Radiant Ceiling" under "z1N Equipment").
> > 
> > I have checked everything I think that may be relevant, but I couldn't
> > find the source of the error.
> > 
> > Could you help me?
> > 
> > Thanks a lot,
> > 
> > Eduard
> > 
> > P.S. I have updated the file: "newtest.idf"
> > 
> > 
> > 
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> > 
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> > 
> > Attachments are not allowed -- please post any files to the
appropriate folder
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> > 
> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf
under the
> > Documentation link and press the "search" button.
> > 
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> > 
> 
> 
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support      
> EnergyPlus-Support@...
>




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